It was announced via Adult Swim’s Facebook page that the Black Clover anime would be returning to Toonami starting in the wee hours of the morning on February 14 in the 2 AM time slot. This will contain the third season of the anime which features the Clover Kingdom vs Spade Kingdom arc.
The same arc is also currently happening in the North American manga releases by VIZ Media who just recently released the 24th volume of the series.
A graphic for the full schedule can be seen below: